Tensions first flared on the night of the presidential election after the results count was inexplicably paused for 24 hours. The final result gave Mr Morales slightly more than the 10-percentage-point lead he needed to win outright in the first round of the race.

The Organization of American States (OAS) is conducting an audit of the votes, and results are expected to be published next week.

But Carlos Mesa – the candidate who finished second – has spoken out against the audit, saying that his party was not consulted.

A former president himself, he asked Bolivia’s congress on Friday to pass an emergency bill to prepare for new elections.